Retroreflective sheetings reflect incident light back toward the originating light source. Retroreflective sheetings are commonly used in, for example, road signs, license plates, barricades and safety garments to improve or enhance their visibility in poor lighting conditions.
Cube corners are commonly used in retroreflective sheetings. Typically, a cube corner includes three mutually perpendicular optical faces that intersect at a single apex. Generally, light that is incident on a corner cube from a light source, is totally internally reflected from each of the three perpendicular cube corner optical faces, and is redirected back toward the light source. Presence of, for example, dirt, water and adhesive on the optical faces can prevent total internal reflection (TIR) and lead to a reduction in the retroreflected light intensity. As such, the air interface is typically protected by a sealing film, but such films typically reduce the total active area, which is the area over which retroreflection can occur. Metallized cube corners do not rely on TIR for retroreflecting light, but they are typically not white enough for daytime viewing of, for example, signing applications. Furthermore, the durability of the metal coatings may also be inadequate.